Publications

See a list of publications below or visit the Photonics academic staff page and click on a particular  member of staff to access their personal web page, which includes a list of their own publications.

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  • Conference paper
    Hong Y, Taengnoi N, Bottrill KRH, Wang Y, Sahu JK, Petropoulos P, Richardson DJet al., 2023,

    Experimental investigation of BDFA-based O-band direct-detection transmission using an optical recirculating loop

    , Publisher: Optica Publishing Group, Pages: 10978-10990, ISSN: 1094-4087
  • Journal article
    Gleneadie HJJ, Fernandez-Ruiz B, Sardini A, Van de Pette M, Dimond A, Prinjha RKK, McGinty J, French PMW, Bagci H, Merkenschlager M, Fisher AGGet al., 2023,

    Endogenous bioluminescent reporters reveal a sustained increase in utrophin gene expression upon EZH2 and ERK1/2 inhibition

    , COMMUNICATIONS BIOLOGY, Vol: 6
  • Journal article
    McCall MW, Koufidis SF, 2023,

    Broadband Bragg phenomenon in a uniform birefringent medium

    , OPTICS LETTERS, Vol: 48, Pages: 1096-1099, ISSN: 0146-9592
  • Journal article
    Tawy G, Minassian A, Damzen MJ, 2023,

    Power-scaled CW Alexandrite lasers

    , APPLIED PHYSICS B-LASERS AND OPTICS, Vol: 129, ISSN: 0946-2171
  • Journal article
    Dvinskikh L, Sparks H, Brito L, MacLeod K, Harding S, Dunsby Cet al., 2023,

    Remote-refocusing light-sheet fluorescence microscopy enables 3D imaging of electromechanical coupling of hiPSC-derived and adult cardiomyocytes in co-culture

    , Scientific Reports, Vol: 13, Pages: 1-14, ISSN: 2045-2322

    Improving cardiac function through stem-cell regenerative therapy requires functional and structural integration of the transplanted cells with the host tissue. Visualizing the electromechanical interaction between native and graft cells necessitates 3D imaging with high spatio-temporal resolution and low photo-toxicity. A custom light-sheet fluorescence microscope was used for volumetric imaging of calcium dynamics in co-cultures of adult rat left ventricle cardiomyocytes and human induced pluripotent stem cell-derived cardiomyocytes. Aberration-free remote refocus of the detection plane synchronously to the scanning of the light sheet along the detection axis enabled fast dual-channel 3D imaging at subcellular resolution without mechanical sample disturbance at up to 8 Hz over a ∼300 µm × 40 µm × 50 µm volume. The two cell types were found to undergo electrically stimulated and spontaneous synchronized calcium transients and contraction. Electromechanical coupling improved with co-culture duration, with 50% of adult-CM coupled after 24 h of co-culture, compared to 19% after 4 h (p = 0.0305). Immobilization with para-nitroblebbistatin did not prevent calcium transient synchronization, with 35% and 36% adult-CM coupled in control and treated samples respectively (p = 0.91), indicating that electrical coupling can be maintained independently of mechanotransduction.
  • Journal article
    Dvinskikh L, Sparks H, MacLeod K, Dunsby Cet al., 2023,

    High-speed 2D light-sheet fluorescence microscopy enables quantification of spatially varying calcium dynamics in ventricular cardiomyocytes

    , Frontiers in Physiology, Vol: 14, Pages: 1-14, ISSN: 1664-042X

    Introduction: Reduced synchrony of calcium release and t-tubule structure organization in individual cardiomyocytes has been linked to loss of contractile strength and arrhythmia. Compared to confocal scanning techniques widely used for imaging calcium dynamics in cardiac muscle cells, light-sheet fluorescence microscopy enables fast acquisition of a 2D plane in the sample with low phototoxicity.Methods: A custom light-sheet fluorescence microscope was used to achieve dual-channel 2D timelapse imaging of calcium and the sarcolemma, enabling calcium sparks and transients in left and right ventricle cardiomyocytes to be correlated with the cell microstructure. Imaging electrically stimulated dual-labelled cardiomyocytes immobilized with para-nitroblebbistatin, a non-phototoxic, low fluorescence contraction uncoupler, with sub-micron resolution at 395 fps over a 38 μm × 170 µm FOV allowed characterization of calcium spark morphology and 2D mapping of the calcium transient time-to-half-maximum across the cell.Results: Blinded analysis of the data revealed sparks with greater amplitude in left ventricle myocytes. The time for the calcium transient to reach half-maximum amplitude in the central part of the cell was found to be, on average, 2 ms shorter than at the cell ends. Sparks co-localized with t-tubules were found to have significantly longer duration, larger area and spark mass than those further away from t-tubules.Conclusion: The high spatiotemporal resolution of the microscope and automated image-analysis enabled detailed 2D mapping and quantification of calcium dynamics of n = 60 myocytes, with the findings demonstrating multi-level spatial variation of calcium dynamics across the cell, supporting the dependence of synchrony and characteristics of calcium release on the underlying t-tubule structure.
  • Journal article
    Damzen M, Xiao H, Jiang X, 2023,

    Alexandrite lasers with blue-diode-pumping

    , Optics Express, Vol: 31, Pages: 5832-5842, ISSN: 1094-4087

    The availability of high-power and high-brightness blue diode lasers makes them attractive as low-cost pump sources for broadly tunable Alexandrite lasers. In this paper we investigate the performance of an Alexandrite laser pumped by a high-power fiber-delivered blue diode module. Output power 1.84 W is achieved, the highest power from blue diode pumped Alexandrite to date. Excellent pump absorption is demonstrated of scrambled pump polarization on both a-axis and b-axis of Alexandrite crystal. Wavelength tuning and dual wavelength operation is produced using the self-birefringent filtering of the Brewster-cut Alexandrite crystal. An analysis is made of laser efficiency and mode formation including the creation of higher-order Laguerre-Gaussian vortex modes (LG01 and LG02). Performance is compared to red diode pumping and prospects for further optimization and power-scaling are discussed.
  • Journal article
    Wang Y, Wang S, Halder A, Sahu Jet al., 2023,

    (INVITED) Bi-doped optical fibers and fiber amplifiers

    , Optical Materials: X, Vol: 17

    Bismuth (Bi)-doped aluminosilicate, phosphosilicate, germanosilicate and high (⩾50 mol%) germanosilicate fibers have shown luminescence around 1.15 μm, 1.3 μm, 1.45 μm and 1.7 μm, respectively. Bi-doped fibers have paved the way for developing optical amplifiers and fiber lasers in the wavelength region of 1150–1500 nm and 1600–1700 nm, where it can serve a wide range of applications in astronomy, imaging, medicine and advanced optical communications. However, spectroscopic study is required to understand the nature of near-infrared (NIR)-emitting Bi active centers (BACs) to improve the efficiency of Bi-doped fiber amplifiers and lasers. In this paper, we review the luminescence properties of Bi-doped glasses as well as Bi-doped fibers with aluminosilicate, phosphosilicate, and germanosilicate glass hosts. Absorption and emission cross-sections of Bi-doped phosphosilicate fibers are reported. In addition, we review the current state of the art of Bi-doped fiber amplifiers development in the second telecom window (O-band) and in the E-band and S-band for the next-generation high-capacity optical communications.
  • Journal article
    Darling C, Davis SPX, Kumar S, French PMW, McGinty Jet al., 2023,

    Single-shot optical projection tomography for high-speed volumetric imaging of dynamic biological samples

    , JOURNAL OF BIOPHOTONICS, Vol: 16, ISSN: 1864-063X
  • Journal article
    Taylor JR, 2023,

    Fiber Laser Driven Three-Micron Source Development Based on Difference Frequency Generation

    , OPTOELECTRONICS INSTRUMENTATION AND DATA PROCESSING, Vol: 59, Pages: 18-27, ISSN: 8756-6990
  • Journal article
    Battle RA, Chandran AM, Runcorn TH, Mussot A, Kudlinski A, Murray RT, Taylor JRet al., 2023,

    Mid-infrared difference-frequency generation directly pumped by a fiber four-wave mixing source

    , OPTICS LETTERS, Vol: 48, Pages: 387-390, ISSN: 0146-9592
  • Conference paper
    Temel T, Murray RT, Wang L, Chen W, Schirrmacher A, Battle RA, Petrov Vet al., 2023,

    Power Scaling of a Narrowband-Seeded PPLN Non-Resonant Optical Parametric Oscillator

    A PPLN non-resonant optical parametric oscillator injection-seeded by narrowband sub-100-mW CW radiation at the signal wavelength produces > 3 W idler average power at 2376 nm for a 20-kHz repetition rate, with sub-2-nm spectral linewidth.
  • Conference paper
    Hong Y, Taengnoi N, Bottrill KRH, Wang Y, Sahu JK, Petropoulos P, Richardson DJ, Calo C, Blache F, Ghazisaeidi A, Renaudier Jet al., 2023,

    Towards Ultra-Wideband Optical Communications Using Novel Optical Amplifiers

    Ultra-wideband transmission over extended bandwidths through the existing fibre infrastructure represents a promising solution. In this paper, we review the recent progress of novel optical amplifiers-enabled ultra-wideband transmission over alternative optical bands.
  • Conference paper
    Taengnoi N, Bottrill KRH, Hong Y, Wang Y, Sahu J, Hanzo L, Richardson DJ, Petropoulos Pet al., 2023,

    Demonstration of 100-km Long O-band WDM Amplified Coherent Transmission

    O-band WDM 100-Gb/s/λ dual-polarization quadrature phase shift keying transmission is demonstrated over a 100-km link, with gain provided by bismuth-doped fiber amplifiers. Two different channel spacings are studied: 0.6nm and 10nm.
  • Conference paper
    Liang M, Minassian A, Damzen M, 2023,

    Acousto-optic Q-switched Alexandrite Laser with Wavelength Tuning and Second Harmonic Generation

    Alexandrite is an excellent solid-state laser medium for high-power Q-switched operation due to its high thermal conductivity (23 Wm−1K−1) and long upper-state lifetime (262 µs). Whilst electro-optically Q-switched (EO-QS) Alexandrite lasers with red diode-pumping have been demonstrated [1], this work presents results of the first ever Acousto-Optic Q-switched (AO-QS) Alexandrite laser. In addition, we present results of the conversion of the output of the wavelength-tuned AO-QS laser to tunable ultraviolet by second harmonic generation.
  • Conference paper
    Xiao H, Jiang X, Damzen MJ, 2023,

    Alexandrite Lasers Operating with High-power Blue-diode-pumping

    Alexandrite is a solid-state laser with excellent thermal properties for power scaling and together with its broad wavelength tunability (~720-820 nm) provides potential for applications in remote sensing, biophotonics, and quantum technologies. Until recently, diode pumping has been predominantly performed by red semiconductor lasers near 638nm, however, blue diodes operating near 445nm have higher emitter power, higher-brightness and low-cost ($/W) making them attractive as alternative pump sources for Alexandrite lasers. This work focuses on the investigation of Alexandrite lasers pumped by a high-power fibre-delivered blue diode module achieving record blue-pumped powers and provides in-depth laser performance characterisation.
  • Conference paper
    Tawy G, Davidson NP, Mennea PL, Churchill G, Wright LD, Bannerman RHS, Smith PGR, Gates JC, Damzen MJ, Gawith CBEet al., 2023,

    375-400nm UV Generation via an Alexandrite laser and Zn-indiffused MgO-doped PPLN Waveguides

    Laser sources in the UV-blue region at around 350-400 nm are of increasing importance for applications including quantum technologies and material processing. To operate in a wide range of environments, these laser sources need to be compact, robust and have low-power and minimal cooling requirements. The work presented here looks at combining rapid progress in two areas of laser development for addressing these applications. Diode-pumped Alexandrite lasers have become a low-cost and simple approach to achieving multi-watt powers in the near-infrared at around 720-800 nm [1]. Zn-indiffused MgO-doped PPLN waveguides have recently demonstrated impressive second harmonic generation (SHG) conversion efficiencies in the near-infrared [2] as well as conversion into the UV with doubling to 390 nm recently reported [3].
  • Conference paper
    Pearce E, Flórez J, Gemmell NR, Karzazi MA, Ma Y, Bressanini G, Battle RA, Murray RT, Kim MS, Phillips CC, Oulton RF, Clark ASet al., 2023,

    Enhancing Nonlinear Interferometers for Imaging with Undetected Photons: Seeding and High-Gain

    Infrared (IR) imaging and spectroscopy is invaluable to many disciplines for its ability to probe molecular responses, from material analysis to diagnostic medicine. However, these applications are often limited by inefficient, noisy detectors. Non-degenerate nonlinear interferometers (NLIs) offer an alternative route through a technique known as imaging with undetected photons [1]. For an NLI producing visible-IR photon pairs, a change in the IR due to an object can be observed as a change to the interference of the visible photons. The IR does not need to be detected, bypassing the need for IR detectors completely.
  • Conference paper
    Krawczyk B, Kudlinski A, Battle RA, Murray RT, Runcorn THet al., 2023,

    Four-Wave Mixing Enhancement in a Yb-doped Photonic Crystal Fiber

    Degenerate four-wave mixing (FWM) in photonic crystal fibers (PCFs) is an effective method for generating near-infrared coherent light across a wide range of wavelengths using compact, low-cost ytterbium or neodymium pump lasers [1]. For many applications, e.g. multiphoton microscopy, increasing the peak power of the short wavelength anti-Stokes sideband generated by FWM is advantageous. Several works have sought to scale the anti-Stokes peak power by optimizing the pump laser and PCF structure but the pump to anti-Stokes conversion efficiency remains limited by pump depletion [2]. By introducing Yb-doping into the core of a PCF designed for FWM, we propose to mitigate the effects of pump depletion by using stimulated emission to replenish the FWM pump energy that is transferred to the anti-Stokes (and Stokes) as it propagates down the fiber. Here we present a novel double-clad PCF with a Yb-doped core and demonstrate, for the first time to the best of our knowledge, that amplification of FWM pump pulses through stimulated emission increases the anti-Stokes power generated by FWM.
  • Conference paper
    Battle RA, Simon D, Xiang Y, Robinson K, Runcorn TH, Murray RT, Takats Zet al., 2023,

    Cellular Level Resolution Ambient Mass Spectrometry Imaging using 3 µm Laser Ablation

    Tissue can be rapidly ablated by lasers with wavelength around λ = 3 µm, which is strongly absorbed by water [1]. Mass spectrometry (MS) analysis of the ablated material can subsequently provide rich chemical data about the molecular content of the tissue. In mass spectrometry imaging (MSI), spatially resolved molecular data is obtained from a sample by collecting multiple mass spectra. From these individual spectra, the spatial distribution of molecules of interest can be mapped. In this work, we report a single-cell level resolution mass spectrometry imaging platform based on laser ablation using a parametric 3 µm laser source and Rapid Evaporative Ionization Mass Spectrometry (REIMS) [2]. The laser source is specifically developed to have high beam quality and sub-ns duration. This has allowed us to overcome previous ambient MSI spatial resolution limits, a key step to translating the benefits of MS analysis to clinical applications.
  • Conference paper
    Taengnoi N, Bottrill KRH, Hong Y, Wang Y, Sahu J, Hanzo L, Richardson DJ, Petropoulos Pet al., 2023,

    Coherent O-band Transmission of 4×25 GBd DP-16QAM Channels Over a 50 km BDFA-Equipped Link

    The first WDM O-band coherent transmission experiment in a BDFA-amplified link is reported. Four 25 GBd DP16QAM channels (4×200 Gb/s) are transmitted over 50 km of fiber, occupying a bandwidth of 4.7 THz.
  • Conference paper
    Wang Y, Halder A, Richardson DJ, Sahu JKet al., 2023,

    A highly temperature-insensitive Bi-doped fiber amplifier in the E+S-band with 20 dB flat gain from 1435-1475 nm

    We report a bismuth-doped fiber amplifier operating in the E+S-band providing a 20.5±1dB flat gain with 5.5±2dB NF from 1435-1475nm for -10dBm input signal. The gain coefficient and temperature-dependent-gain coefficient are 0.065dB/mW and -0.005±0.001dB/, respectively.
  • Conference paper
    Battle RA, Simon D, Xiang Y, Robinson K, Runcorn TH, Murray RT, Taylor JR, Takats Zet al., 2023,

    High resolution mass spectrometry imaging using 3 micron laser ablation

    , ISSN: 1605-7422

    We report a single-cell level resolution (≤10 µm), laser desorption-based mass spectrometry imaging platform. An optical parametric amplifier is used to generate ∼100 ps, 200 nJ pulses at around 3 µm with a maximum repetition rate of 500 kHz. The pulses are tightly focussed on to fresh frozen animal tissue samples with a thickness of 10 µm. Small volumes of tissue are readily ablated by the laser and are subsequently chemically analyzed using a Rapid Evaporative Ionization Mass Spectrometry (REIMS) source installed on a time of flight mass analyzer. Raster scanning the samples through the laser focus enables the acquisition of mass spectrometry data which can be processed into images with pixel size 10 µm without oversampling, corresponding to cellular level resolution.
  • Conference paper
    Geberbauer JWT, Murray RT, Runcorn TH, Kerridge-Johns WRet al., 2023,

    Yb fiber vortex laser using an interferometric mode converting output coupler

    , ISSN: 0277-786X

    We apply mode transformation to an Yb fiber laser for direct generation of a first order vortex mode (LG01), yielding LG01 power of 5 W at 96 % purity (from modal decomposition) with 16 W pumping. The laser used standard single mode Yb doped fibers operating at 1064 nm. A free-space Sagnac interferometer formed one reflector of the cavity by feeding back the internal Gaussian mode of the fiber laser and output coupling a LG01 via interferometric mode transformation. It was stable over hours of operation and days of inactivity, and was insensitive to polarisation. The maximum output power was only limited through heating of a optical element, which could be mitigated with thermal management. We also show that additional spiral phase plates (SPPs) are a route to higher purity, higher order vortex modes than with SPPs alone due to improved intensity matching between LG01 and higher order states.
  • Conference paper
    Murray RT, Wang L, Chen W, Battle RA, Schirrmacher A, Büttner E, Petrov Vet al., 2023,

    Narrowband seeding of a PPLN nonresonant optical parametric oscillator

    , ISSN: 0277-786X

    We present a nanosecond, non-resonant optical parametric oscillator (NRO) based on a 20 mm long periodically-poled LiNbO3 (PPLN) crystal operating at 30-70 kHz. Pumping with a nanosecond Nd:YVO4 laser at 1064 nm in a double-pass configuration, the signal plus idler average output power reached 1.2 W for a pump level of 4 W (at 35 kHz repetition rate). Narrowband seeding with a Tm-fiber laser is employed to narrow the linewidths of the signal to 0.8 nm and the idler to 2 nm. Continuous-wave seed levels as low as 2 mW were sufficient to produce the effect which means that this technique could be useful for single-frequency operation using DFB seed laser diodes. At higher pump power levels > 4 W, the linewidth narrowing effect produced by the seeding was insufficient to prevent broader linewidth operation of the NRO signal and idler outputs. Pumping the NRO at higher repetition rates to scale the average output power of the NRO whilst remaining in the narrow linewidth operation mode is discussed.
  • Conference paper
    Wang Y, Halder A, Sahu J, 2023,

    Bi-doped fiber amplifier operating in the wavelength range of 1430-1500 nm

    We report Bi-doped germanosilicate fiber amplifier with a 38dB gain at 1455nm and >20dB gain from 1430-1495nm for an input signal of -23dBm. The temperature-dependent-gain coefficients over temperatures spanning from -60°C to 80°C are <0.06dB/°C.
  • Conference paper
    Taengnoi N, Bottrill KRH, Hong Y, Wang Y, Sahu J, Hanzo L, Richardson DJ, Petropoulos Pet al., 2023,

    Demonstration of 100-km Long O-band WDM Amplified Coherent Transmission

    O-band WDM 100-Gb/s/λ dual-polarization quadrature phase shift keying transmission is demonstrated over a 100-km link, with gain provided by bismuth-doped fiber amplifiers. Two different channel spacings are studied: 0.6nm and 10nm.
  • Conference paper
    Rowe-Brown L, Curry N, Meyler S, Moderau N, Dunsby Cet al., 2023,

    Oblique plane microscopy for 3D, multi-color, 8-day time-lapse imaging of genetically heterogeneous breast cancer spheroids in 384-well plates with quantitative 3D analysis

    , Conference on Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues XXI, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 1605-7422
  • Journal article
    Koufidis SF, McCall MW, 2022,

    M?bius transformation and coupled-wave theory: Complete identification of the transfer matrix

    , PHYSICAL REVIEW A, Vol: 106, ISSN: 2469-9926
  • Journal article
    Rahman T, Baxan N, Murray R, Tavana S, Schaer T, Smith N, Bull J, Newell Net al., 2022,

    An in vitro comparison of three nucleus pulposus removal techniques for partial intervertebral disc replacement: An ultra-high resolution MRI study

    , JOR Spine, ISSN: 2572-1143

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